Working out how to produce it at lower cost is a development effort - that takes time, likely months to years. While in the long run it is helpful, in the sort run it'd increase time and cost to get stuff in people's arms. Also, Moderna and Pfizer vaccines require deep refrigeration, that makes them incredibly had to work with in many places - these are not vaccines you want in areas with weak infrastructure, even if the cost per dose came down some
In practice, working out how to produce something at a lower cost generally comes from producing more of it and doing small scale optimizations, while under pressure to reduce costs.
See
What Is Wright's Law | Learning Curve of Innovation -- make more of stuff, and in almost every industry, price drops. There has to be an incentive to actually capture such efficiencies.
Right now, due to IP law, there is little incentive in any company besides Phizer and Morderna to try to make the tricky lipid wrapping process of mRNA vaccines cheaper, and setting up a factory in places that grant them patent monopolies to try to do that isn't going to be viable. OTOH, the AZ/JJ/NV and even the Chinese and Russian vaccines are alternatives to the mRNA ones, so there is some price pressure on M/Pf. And places that don't respect US IP monopolies are trying to scale up mRNA based vaccines as well.
So there is hope that the costs will plummet.
There are legal issues to removing patent protection - it isn't a thing the government can do on a whim, and doing so would freak the ever loving frak out of every technology company in the nation. A government trying to unilaterally remove patent protection probably means lawsuits, because no company wants their rights ripped away. And you should not expect the court precedent to go the way you want. While the courts might decide that a form of "eminent domain" may be exerted for a crisis in the US... we do not now have a crisis of production in the US. And I don't think there's a precedent for asserting such government rights on behalf of people of other nations.
No, this is what governments do. They set the rules that determine what the legal issues are. And governments determine what lawsuits are allowed.
There is precident that they can retroactively increase the length of protection under the IP statute, and the US supreme court said "this is completely up to congress". It would be very strange if congress had nearly complete authority to extend the duration of patents and trademarks and dismissed all recourse from people harmed by that, and very limited ability to reduce the durations. But I guess corporations are people and money is free speech, so who knows what the SCOTUS will come up with next.
Many nations already have exceptions for bio pharmaceutical patents, including mandatory licensing, including for domestic use. OTOH, the USA usually places IP law demands in international trade treaties, which can bind other countries even if there is no domestic justification for the monopoly granted.
I don't see the incentive for the USA to do this. Pharma are good campaign contributors, and the USA has enough domestic manufacturing they can vaccinate their population. But the US-led world order that came out of the cold war is sort of limping along with blood leaking out at this point; maybe it will get bandaged up, or maybe not.
And IP law only holds if the benefits outweigh the costs.
My criticism wasn't exclusive to pharmaceutical companies. I think there is a lot that rich countries should be doing here well. But I think focusing only on the role of wealthy countries and ignoring the profit motive among pharmaceutical companies, and dismissing things like ending the patent protection, really plays into the hands of greedy corporations that are positioning themselves to get richer and stronger off a pandemic that effects people from every country, every level of society and shouldn't be about making money
India, as I understand it, isn't paying much attention to international patents for domestic consumption.
The mRNA ones are tricky enough that nobody but the inventors can make them yet. But AZ/JJ and the like are more traditional.
AZ in particular is producing the doses at basically cost; after paying for new factories, of course. The deal was that Oxford found a 2nd or 3rd tier pharma manufacturer who was willing to become much larger in exchange for producing a pile of vaccine that wasn't going to make them money directly; instead, they'll have goodwill and a much larger manufacturing base, which they can use to produce
other stuff.
The medicines are really being priced for "we want it to be low enough that everyone on the planet uses ours", and the raw number of alternatives is also huge at making everyone keeps prices down. If one cost 10x as much as another, the other one will get used.
Right now, the prices are pretty insanely low, considering that the real problem is
total supply not price per dose.